Hydraulic tracer control



Aug. 20, 1957 Filed Feb. 16, 1954 F. LA MONICA HYDRAULIC TRACER CONTROL 5 Sheets-Sheet l h VM W;

Aug. 20, 1957 Filed Feb. 16, 1954 F. LA MONICA 2,803,095

l-IYDRAUL-IC TRACER CONTROL 5 Sheets-Sheet 2 '1 I 10 5 1 g o o -11 11- o o \I o O O o INVENTOR.

HTTOFA/E) Aug. 20, 1957 F. LA MONICA HYDRAULIC TRACER CONTROL 5 Sheets-Sheet 5 Filed Feb. 16. 1954 Aug. 20, 1957 F. LA MONICA 2,803,095

HYDRAULIC TRACER CONTRQL Filed Feb. 16, 1954 5 Sheets-Sheet 4 u will, ......m.

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HYDRAULIC TRACER CONTROL Aug. 20, 1957 Filed Feb. 16, 1954 5 Sheets-Sheet 5 HYDRAULIC TRACER CONTROL Frank La Monica, Unionville, Conn., assignor to The United Tool & Die Company, Elmwood, Conn., a corporation of Connecticut Application February 16, 1954, Serial No. 410,688

8 Claims. (Cl. 51100) This invention relates to a hydraulic tracer control and more particularly to a tracer mechanism for controlling machines such as grinders, shapers and the like.

The primary object of this invention is to provide a hydraulic tracer control which is particularly adapted for grinding machines.

A further object is the provision of a hydraulic tracer control for grinding machines which is highly eflicient in its operation, simple in construction and easy to install in conventional grinding machines.

A still further object of the invention is the provision of improved means for adjustably mounting the template, which is included in the tracer mechanism, on the machine.

Further objects and advantages of this invention will be more clearly understood from the following description and the accompanying drawings in which:

Fig. 1 is a side view illustrating the right hand side of a conventional grinding machine including the mechanism embodying the present invention.

.Fig. 2 is a side view of the template holder illustrating the adjustment thereof.

'Fig. 3 is a rear view of said machine and mechanism.

Fig. 4 is a side view, partly in vertical section, .illustrating the left hand side of the machine.

Fig. 5 is an .enlarged rear view of portions of the machine illustrating the mechanism of the present invention.

Fig. 6 is a fragmentary sectional view taken on line 6-6 of Fig. 5.

Fig. 7 is a further enlarged view, in central vertical section, of the hydraulic cylinder and the piston therein.

Fig. 8 is a further enlarged view, .in central vertical section, of the solenoid valve included in said mechanism.

Fig. 9 is a further enlarged view, in central vertical section, of the "hydraulic valve included in said mechanism.

.Fig. -10 is a diagrammatic view illustrating the hydraulic and electrical circuits included .in my improved hydraulic tracer mechanism.

Fig. -11 is .a sectional view-of-a portion ofthe machine on line 11-11 of Fig. 4.

iInLthe embodiment illustrated in the drawings, my improvided hydraulic control .is .shown as installed in a conventional horizontal surface grinding machine :which includes a base 5 having a saddle 6 that is slidable 'on ways 7 on said base. .A table 8 is carried'on the saddle 6 .and is slidable :on ways .9 in a direction crosswise to the sliding movement of the saddle.

The said grinding machine further includes a column :10 which is vertically .slidable .in 'column ways .11 on the base 5. The "said column-carries a spindle -12-'t-hat extends perpendicularly ..to the direction of movement of the -.tab1e.8 and .carriesa grinding wheel 13. -Anelectric motor 14 is mounted upon the column 10 and drives United States Patent C "ice the said spindle through a suitable driving belt 15. The column 10 is vertically supported upon a shaft 16 which is threaded to a horizontal projection 17 that extends from the base 5, as clearly illustrated in Fig. 4.

In the normal operation of the said grinding machine, the saddle is moved rearwardly and forwardly upon the base 5 in a direction parallel to the axis of the grinding wheel by means of a hand wheel 18, and the table 8 is moved transversely of the saddle and the axis of the grinding wheel by means of a second hand wheel 19. The column 10 and, consequently, the grinding wheel 13' are moved vertically by rotation of an elevating hand wheel 20 which, as illustrated in Fig. 6, is secured to and rotates a shaft 21 and the worm 22 thereon and thereby rotates a worm gear 23 that is splined to the shaft 16, but through which the said shaft is slidable.

'In the construction shown, the said worm gear 23 is contained within a housing 24 that is mounted upon the top of the column 10. The said worm gear is retained against vertical movement relatively to the housing 'by a radial bearing 25 that is mounted in the base 26 of the housing 24, a radial bearing 27 that is mounted in a bearing plate 28 at the top of the said housing, and by means of suitable sleeves 29 and 30.

In adaptation of my present invention to the above described grinding machine, a vertical cylinder 31 is mounted upon the column 10 in inverted position over the bearing plate 28 and said cylinder is secured to said column by means of bolts 32 which extend through a flange 33 on said cylinder, the plate 28, the housing 24 and are threaded into the top of the column 10 'as clearly shown in Fig. 5. The shaft 16 is extended into said cylinder and has secured to the upper end thereof a piston 34 which is rotatably connected to the spindle by means of suitable thrust bearings 35 and 36.

In the normal hand operable condition of the grinding machine, the .column 10 is supported upon the projection 17 by the shaft 16 through engagement of the said piston with an annular shoulder 37 at the .top of the cylinder 31 which surrounds a recess 38 in the head of the cylinder. When the elevating hand wheel 20 is rotated, the worm 22 will rotate the worm gear 23 and the said gear will rotate the shaft 16 in the projection 17 and relatively to the piston 34 and, by means of the threaded connection with said projection, raise or lower the column 10 so as to vertically position the grinding wheel 13 with relation .to the :work-piece upon the table 8. It will be understood that the entire weight of the column 10 and the motor 14 thereon is carried by the shaft 16 and the projection 17 and that said column is lowered under its own weight, to lower the wheel 13 upon the work-piece, when .the hand wheel 20 is rotated in the proper direction.

In the .embodimentof the present invention illustrated, there is included a template-operated valve 39 which is preferably constructed as illustrated in Fig. 9 and as fully .described in my copending application Serial No. 404,173, .filed January 15, 1954. The said valve includes .a cylindrical housing 40 having an axial bore 41 in which there is slidably .contained a valve plunger 42 which is moved (axially against the tension of 'a spring 43 by The said tracer carrier supports Said template is carried on the saddle 6, by means to be hereinafter described, and is movable therewith in a direction perpendicular to the axis of the .valve 39 and-is engaged by the .tracer-rnember-46 to cause lateral movement of the tracer carrier -.44.an-d axial movement :ofthe valve plunger 42.

As described in the said co-pending application, the

housing 40 contains an annular recess 48 which communicates with an inlet pipe 49 through a radial passage 49-a. A second radial passage 50 extends from the bore 41 and communicates with an outlet pipe 51. When the carrier 44 is moved in any lateral direction by the template 47, the plunger 42 will be moved axially so that the peripheral edge 52 of said plunger will move towards the adjacent edge of the bore 41 and thereby act to move the valve towards closed position and reduce the flow of fluid therethrough. In its normal condition, that is, when the tracer 46 is not engaged by the template 47, the plunger 42 is disposed in a predetermined partially open position which permits a constant flow of hydraulic fluid through said valve.

In Fig. 10, it will be seen that the hydraulic system incorporated in my invention preferably includes a suitable hydraulic pump which generally comprises a hydraulic fluid reservoir 53 and a pump 54 which is driven by means of a suitable motor 55. The said pump is connected through a suitable flexible hose 56 with a pipe 57 that communicates with the recess 38 in the top of the cylinder 31 through a normally closed solenoid valve 58 such as shown in Fig. 8. The pipe 57 is connected through a T to the inlet pipe 49 of the valve 39 and the outlet pipe 51 of said valve is connected to a flexible hose 59 which provides a return to the reservoir 53. As further illustrated in Fig. 10, the motor 55 and the solenoid 58 are connected in parallel in an electric circuit which is controlled by a suitable electric switch 60.

Assuming that the mechanism is in the normal position shown in Fig. 7, wherein the piston 34 is in engagement with the shoulder 37 at the top of the cylinder 31, it is possible to place the mechanism in condition for operation by the hydraulic tracer control in the following manner:

The hand wheel 20 is rotated to raise the column and the valve 39 thereon to a position wherein the tracer member 46 will be located substantially above the highest point of the template 47 which is to be positioned in the holder therefor. The template 47 is then placed in the holder in approximately the proper location with respect to the work-piece on the table 8 and the saddle 6 is moved inwardly or outwardly, as the case may be, by means of the hand wheel 18 to locate the lowest point on the template directly under the tracer member 46. The switch 60 is then closed, thereby simultaneously energizing the pump motor 55 and the solenoid valve 58 to cause pumping of the hydraulic fluid and opening of said solenoid valve. Since the tracer wheel 46 is not in engagement with the template at this time, but is located thereabove, the hydraulic valve 39 will be in its open position and, upon reference to'Fig. 10, it will be understood that the hydraulic fluid will circulate through the pipes 56, 49, the open valve 39 and the pipes 51 and 59 at a constant pres sure. Since the valve 39 is open, the pressure required to circulate fluid through the valve is considerably less than that required to overcome the weight of the column 10 which is resting on the piston and consequently no fluid will pass through the pipe 57 and the solenoid valve 58 except that which is necessary to fill the recess 38.

The hand wheel is then rotated to lower the entire column 1t and the valve 39. When the tracer member engages the template, the plunger 42 in the valve 39 will move toward closed position and thereby resist the flow of fluid therethrough and cause an increase in pressure in the cylinder 31 through the pipe 57 and the solenoid valve 58. The pressure in the cylinder will build up until it equals the pressure required to force fluid through the valve 39. At this point a static condition is reached and the column is then supported by the hydraulic fluid in the cylinder.

The piston, however, it still against the shoulder 37 at the top of the cylinder so the hand wheel is rotated to lower the piston. Since the column 10 is being supported by the hydraulic fluid in the cylinder, the piston will move ,4 downwardly relatively to the cylinder and the space above the top of the piston will be filled with hydraulic fluid under constant pressure as the piston descends. The piston is lowered to a point intermediate the ends of the cylinder to permit the necessary travel of the column 10 in both an upward and a downward direction during the grinding operation.

The saddle is then moved outwardly, to the left in Fig. 1, thereby moving the template relatively to the tracer member which will operate the valve 39 to cause corresponding movement of the column 10, until the tracer member is the starting point on the template and said template is then adjusted to properly position it with relation to the workpiece on the table 8 and the machine is ready to commence the grinding operation.

The saddle 6 is then moved slowly inwardly and thereby moves the template relatively to the tracer member on the valve 39'. As the template engages the tracer member, the plunger 42 is in the valve 39 will be moved axially in accordance with the contour of the template to thereby change the rate of flow through the valve 39 which will vary the pressure of the hydraulic fluid in the cylinder 31 to either raise or lower the column and the grinding wheel.

From the above description it will be seen that when the contour of the template is such that it urges the tracer carrier laterally, the plunger 42 in the valve 39 moves towards closed position and thereby resists the flow of fluid through the valve and causes the said fluid to enter into the recess 38 in the head of the cylinder 31. The pressure of said fluid will then force the cylinder upwardly away from the piston34 and thereby raise the entire column 10 and the grinding wheel 13 thereon until the force of the template against the tracer member 46 is released and the plunger is permitted to move towards open position at which time the circulation of the fluid through the valve 39 will be increased until a point has been reached wherein the pressure between the cylinder 31 and the piston 34 is equal to the pressure required to force fluid through the valve 39 to thereby balance the weight of the column 10 and support the grinding wheel 13 relatively to the table 8 in accordance with the height of the template 47.

It will, therefore, be understood that fluid is constantly circulating through the valve 39, but that the pressure between the cylinder 31 and the piston 34 is varied in accordance with the condition of the valve. Assuming that the weight of the column 10 is 800 pounds, the area of the piston is eight square inches and the pressure supplied by the pump 51 is 200 pounds per square inch, the amount of pressure required in the cylinder 31 to balance the column 10 will then be pounds per square inch and this means that a surplus pressure of 100 pounds per square inch is by-passed through the valve 39 into the reservoir 53.

When the opening in the valve 39 is reduced, it will reduce the by-passing of the fluid therethrough and this will increase the pressure in the cylinder 31 and thereby cause raising of the column 10 and the grinding wheel 13 with relation to the work-piece on the table 8. When the opening in the said valveis increased, it will increase the by-passing of the fluid pressure and this will reduce the fluid pressure within the cylinder 31 and thereby cause lowering of the column 10 and of the grinding wheel with relation to the said work-piece.

When the cylinder 31 is raised with relation to the piston 34, as shown in Fig. 5, and the motor 55 is de-energized by opening of the switch 60, de-energization of the solenoid valve 58 will also occur and the said valve will simultaneously close and thus retain the fluid in the cylinder and prevent the column 10 and the grinding wheel 13 from dropping. Upon the closing again of the switch 60 the solenoid valve will open and, since the valve 39 is in the same condition, will be immediately applied without affecting the vertical position of the column. When it is desired to raise the piston so that it will engage the top of the cylinder and thereby raise the grinding wheel out of contact with the work-piece, the shaft 16 is rotated in the nut 17 by the hand wheel 20 until the piston engages the top of the cylinder and raises the column and the grinding wheel. As soon as the turning of the said hand wheel 20 is begun, the pressure of the template against the tracer member 46 will be reduced, thereby causing opening of the valve to permit the passage of the fluid displaced by the piston from the cylinder through said valve and to the reservoir 53 so that the said cylinder is being emptied of the fluid therein as the piston is raised and, when the piston engages the top of the cylinder, further movement of the piston by rotation of the hand wheel will raise the cylinder and the column and the entire weight of the said column will then be supported upon the piston and the shaft.

It will be understood that the grinding machine may be operated in the normal manner by rotation of the hand wheel 20 and thereby elevating or lowering the grinding wheel relatively to the work-piece independently of the tracer controlled system and that, when it is desired to put the said system into operation, it is merely necessary to close the switch 60 and then lower the column until the tracer member engages the template; the valve 39 will then open and supply fluid under pressure to the cylinder and said fluid will take over the load of the column and raise or lower said column in response to the operation of the valve by the template.

As illustrated in the said drawings, the template 47 is shaped in accordance with the shape which it is desired to grind upon the work-piece 61 with the grinding wheel 13. The said template is mounted in a slot 62, Figs. 1 and 3, in the edge of a template support 63 and is secured therein by means of a plurality of set screws 64. The said support 63 is pivotally mounted upon a vertical post 65, Figs. 1 to 3, which is vertically adjustable and secured to a vertical slide 66 that is slidably mounted upon an outright supporting post 67. The said supporting post is horizontally slidable on a supporting base 68 that is mounted upon the saddle 6. Adjustment of the template with relation to the tracer member so that it will correspond with the position of the work-piece 61 relatively to the grinding wheel, the said template may be moved vertically by means of a screw 69 that connects the slide 66 to the supporting post 67 or it may be moved horizontally by means of the lead screw 70 which moves the said supporting post 67 on the base 68.

As illustrated in Fig. 2, the template support 63 is preferably pivoted upon the post 65 by a pivot pin 71 and is adjustably secured to said post by means of clamping screws 7272 which extend through arcuate slots in the post and are threaded to the support. The said support may, therefore, be adjusted to any desired angle and, as shown, may thereby support a straight edged template 73 so as to produce a tapered surface of a corresponding angle upon the work-piece being ground in the machine.

In order to permit the initial entry of fluid into the cylinder 31, there is provided a suitable bleed valve 74 which may be opened to allow the escape of air from the cylinder as the fluid enters it. I also provide a suitable vent 75 at the bottom of the cylinder so as to prevent compression of air below the piston 34 which would otherwise be forced through the bearings in the housing 24 and interfere with the proper lubrication of said bearings.

I claim:

1. In a machine including a base, a column vertically slidable on said base and urged to move downwardly thereon by its own weight, a projection on said base, a vertical shaft threaded-to said projection and means secured against vertical movement relatively to the column for rotating said shaft to adjust the vertical position of the column on the base by means of the threaded connection between the shaft and the projection, the improvement including means providing a sliding connection between the said rotating means and the shaft, a piston mounted upon the upper end of the shaft, a cylinder mounted upon said column and containing said piston, means for supplying hydraulic pressure between said piston and cylinder to raise the column on the base independently of the shaft, a valve for varying the pressure supplied to the cylinder, a template, and means controlled by said template for operating said valve.

2. In a machine including a base, a column movable on said base and urged to move downwardly thereon by its own weight and a shaft threaded to said base and extending vertically therefrom, a worm gear splined to said shaft and secured against vertical movement relatively to the column, a piston mounted upon the upper end of the shaft, a cylinder containing said piston and secured to the column; the said piston being engageable with the top of the cylinder to normally support the column upon the shaft, means for rotating the-said worm gear to vary the vertical position of the column relatively to the base by means of the threaded connection between the shaft and the base, means for supplying a hydraulic pressure medium to the cylinder and over the piston for raising the column independently of the said shaft, a normally closed valve for retaining said pressure mediumwithin the cylinder when the said supply means is inoperative, means for opening said normally closed valve upon initiation of the operation of said supply means, a valve for varying the pressure supplied to the cylinder, a template, and means controlled by said template for operating said valve.

3. In a machine including a base, a column movable on said base and urged to move downwardly thereon by its own weight, a nut extending from said base and a shaft threaded to said nut and extending vertically therefrom, a piston mounted upon the upper end of the shaft, a cylinder inverted over the piston and secured to the column, an abutment adjacent the top of the cylinder engageable by the piston for normally supporting the column upon the shaft, a rotatably mounted member slidably connecte'd'ot the shaft and secured against vertical movement relatively to the column for rotating said shaft to raise and lower the column upon the base, a source of hydraulic fluid under pressure, a supply pipe between said source and the cylinder for supplying the fluid to the cylinder and over the piston to raise the column on the base independently of the said shaft, a normally closed electrically controlled valve connected in said pipe for retaining the fluid within the cylinder to thereby prevent the column from dropping when the said pressure source is inoperative, an electric motor for operating said pressure source, an electric circuit having said motor and said normally closed valve connected in parallel therein, an electric switch for closing said circuit and simultaneously energizing said motor and opening said valve, a return pipe for returning the hydraulic fluid to the pressure supply source, and a template-controlled valve in said return pipe for controlling the return of the fluid to thereby vary the pressure supplied to the cylinder.

4. In a machine including a base, a column vertically movable on said base and urged to move downwardly by its own weight and a shaft secured to the base and extending upwardly therefrom, a piston mounted upon the upper end of the shaft, a cylinder inverted over said piston and secured to the said column, pump means connected to said cylinder for supplying hydraulic fluid under pressure between the cylinder and the piston to raise the column relatively to the shaft, a valve for varying the pressure in said cylinder, a template, means controlled by said template for operating said valve, and means for raising and lowering the column independently of said template-controlled valve.

5. In a machine including a base, a column vertically slidable on said base and urged downwardly thereon by its own weight, and a shaft threaded to the 'base and projecting upwardly therefrom, a piston rotatably mounted on the upper end of said shaft, a cylinder inverted over said piston and secured to the column, abutment means between the cylinder and the piston for supporting the column upon the said shaft, a member secured against vertical movement relatively to column and slidable on the shaft, said member being adapted to rotate said shaft to raise and lower the column by means of the threaded connection, a pressure supply source including a reservoir, a pump in said reservoir, an electric motor for driving said pump, a conduit extending from said pump into the cylinder above the piston for supplying fluid under pressure to said cylinder to raise the column upon the piston, an outlet in said conduit, a template-controlled hydraulic valve connected to said outlet for controlling the amount of fluid released from the conduit to thereby vary the presure of the fluid in said cylinder, a return conduit from said valve to the reservoir, a normally closed solenoid valve in said conduit between the outlet and the cylinder and an electric circuit in which the said motor and solenoid valve are connected in parallel.

6. In a machine including a base, a column vertically slidable on said base, a shaft between the base and column, a pressure operated means between the shaft and the column for varying the position of the column on the base independently of the shaft, a tracer valve carried by the column for controlling said pressure means, a work table movably mounted upon the base, an adjustable support carried by said Work table, and a template mounted upon said support for operating the tracer valve.

7. In a machine including a base, a column vertically slidable on said base and movable downwardly thereon by its own weight, a shaft threaded to said base and extending vertically therefrom, said column being normally supported by said shaft, means for rotating said shaft to vary the vertical position of the column relatively to the base, tracer means carried by said column, pressure means between the shaft and the column controlled by said tracer means for varying the position of the column 'on the base independently of the shaft, a work table movably mounted upon the base, an

adjustable support carried by the said table, and a template mounted upon said support for operating the tracer means.

8. In a machine including a base, a column vertically slidable on said base, a shaft having a threaded connection to the base, and projecting upwardly therefrom within the column, a piston upon the upper end of said shaft, a mechanism for rotating said shaft mounted upon the top of the column and including a Worm gear slidable upon the shaft and keyed thereto below the piston, a cylinder inverted over said piston and mounted upon the column over the said rotating mechanism, means for supplying pressure to said cylinder above said piston including a control valve for controlling the said supply of pressure to the cylinder, a conduit connecting said valve with the upper end of the cylinder, a separate valve in said conduit adapted to close upon the termination of the supply of pressure to the cylinder, a table movably mounted upon the base, and a template carried by said table for operating the control valve.

References Cited in the file of this patent UNITED STATES PATENTS 1,178,733 Koken Apr. 11, 1916 2,039,294 Campbell May 5, 1936 2,051,430 Wall Aug. 18, 1936 2,072,336 Johansen Mar. 2, 1937 2,157,471 Armitage May 9, 1939 2,231,433 Blum Feb. 11, 1941 2,250,241 Thalman July 22, 1941 2,311,864 Parsons Feb. 23, 1943 2,359,112 Hymans Sept. 26, 1944 2,603,041 Bowen July 15, 1952 FOREIGN PATENTS 464,306 Great Britain Apr. 15, 1937 850,860 Germany Sept. 29, 1952 891,173 Germany Sept. 24, 1953 920,043 Germany July 8, 1949 

